Despite multidisciplinary specialty care, glycemic control remains suboptimal in many pediatric diabetes centers world-wide. Adolescents with type 1 diabetes are at high risk for suboptimal control due in part to behavioral and emotional challenges. Behavioral challenges come in the form of poor adherence to the diabetes management regimen - a common problem facing adolescents with type 1 diabetes. Emotional challenges include depression, which is 2-3 times more prevalent in adolescents with type 1 diabetes than their adolescent counterparts without diabetes. Further, both poor adherence and depression are linked with problematic family functioning (e.g., family conflict) in promoting suboptimal control. Effective interventions are available, however, these family-based interventions aimed at adherence promotion and improved family functioning do not typically have targeted deployment in adolescents with clinically significant, comorbid depression. These adolescents with significant depressive symptoms may be treated with effective psychological interventions, typically cognitive-behavioral in nature, but these interventions do not always consider the context of type 1 diabetes and its associated management. Thus, there is an unmet treatment need for depressed adolescents with type 1 diabetes. To address this unmet need, this study employs a randomized, controlled design to test a new, family-based, cognitive-behavioral intervention to reduce depressive symptoms, improve family functioning, and improve adherence. The intervention is delivered in two phases (1 - reduction of depressive symptoms and family conflict, 2 - adherence promotion) as efforts to improve adherence will have a greater likelihood of success if individual and family functioning variables are addressed first. Fifty-two adolescents and their primary caregivers will be enrolled in the study. Given the absence of this type of intervention and the significance of the problem, this study is timely and important, as it has the potential to positively impact diabetes-specific health outcomes.